In praise of vanished countries

23 years after the fall of the USSR it's becoming hard to remember that the Baltic States were once considered to be "dead countries" by stamp collectors: countries whose stamp-issuing days were deemed to be over. Oops!
The atlas is just littered with vanished stamp-issuing entities. Not just independent/renamed/reshuffled colonies but entire constellations of countries which no longer issue stamps. Kenya-Uganda-Tanganyika anyone? (yes, this used to be one stamp-issuing entity...)
There is a parallel to this concept in postal history, even in the pre-stamp area. The map of Europe was just as unstable before stamps were introduced as afterwards, especially during the Napoleonic era.
Prussia initially did quite nicely out of Napoleon, thank you very much. Prussia gained enormous slabs of territory along the Rhine and became the largest of the reorganized "German States". But it all went terribly wrong in 1806, when Prussia decided enough wasn't enough and Napoleon opined that on the contrary, perhaps enough was too much! Prussia lost all territory West of Magdeburg and two new states were created out of the wreckage: the Grand Duchy of Berg and the Kingdom of Westphalia (not to be confused with the Duchy of the same name).
For Russian mail to the West, this was a disaster! Before 1806, Prussia could be relied on to transport Russian mail all the way to the borders of France, the Netherlands and (what was to become) Belgium. Now these two new enormous lumps on the map were in the way. The new states (which lasted all of 7 years) introduced new currencies, postal rates, town postmarks and transit markings, all of which have been admirably documented by obsessive German postal historians.
The first sign that Russian mail had run into a new border came at Magdeburg, where Prussia ended and Westphalia began. The Westphalians applied a new transit marking "PRUSSE P.M." which stands for "(from)Prussia via Magdeburg". This example is particularly crisp:

March 1809, St.Petersburg via Memel and Magdeburg to Frankfurt

The reverse reveals that the sender prepaid 13 gute Groschen foreign postage. Prussia kept 7 1/4 g.G for the Memel-Magdeburg trip and passed the remaining  5 3/4 g.G on to Westphalia (magenta notation at lower left). After that, things get fuzzy but Westphalia felt it got enough money to stamp the letter FRANCO and sent it on to Frankfurt.

This is a simple one: only one of the new states to deal with. mail to France and Holland had to pass through both Westphalia AND Berg and the resulting puzzles are maddening, particularly as borders shifted a few times...

But still! Westphalia may be a "dead country" but it offers a lot of postal history fun, even without stamps.